Survey of Consumption water resources priorities in normal conditions and drought (case study: Bandar Abbas city )

Water and energy are the most important sources that have been faced with a serious crisis, over the last century. Iran is at risk according to lack of water resources and tenses. This country, among arid and semi- arid countries in the world, is facing with increasing of water demand due to population growth, urbanization and development of agricultural and industrial sections. The continued increase in amount of demand causes to increase the gap between supply and demand of water in the future. Therefore in such areas to avoid crisis situations, it is essential to manage water resources .Bandar Abbas city is located in desert environment of Hormozgan province, Iran. This city, because of the relatively low rainfall and the high coefficient of variation, has faced with the drinking and agricultural water crisis. In the other hand, because of the high population growth and development that has occurred in the recent years, demand to water resources has increased in Bandar Abbas, day by day. Bandar Abbas city, with average rainfall of 188 millimeter and high coefficient variance (C.V) rates, needs to be investigated from the aspect of suppling drinking water.The aim of this study is to prioritize drinking water resources in drought and normal conditions and eventually determining the best choices for drinking water source for Bandar Abbas city. Therefore, prioritize of water resources for efficient use in critical condition, can be an effective step. Decision making is essential in many fields to find the best approach. The aim of the present study is to prioritize the supply resources of drinking water in Bandar Abbas. In this study, identification of the affecting factors for prioritization has been done, using the TOPSIS model as one of the decision making models (AHP). To determine the best source of water, natural and human criteria was used. In this model, the first step was identifying and collecting data and calculating some factors that related to water resources, in the eleven region of Hormozgan province (surrounding Bandar Abbas). Based on the data obtained from selected regions, the intensity and importance of each area was defined by numbers. The next step was forming a decision tree with hierarchical structure. The tree was designed in descending order with three levels that contains of goal (areas priority), criteria and options (eleven areas around the city of Bandar Abbas), respectively from highest to lowest level. Then, the decision matrix was formed with quantitative criteria in the TOPSIS model. Afterward, six steps applied for assessment and calculation to gain the results. Thirty questionnaires were used to determine the weights of the criteria. The matrix which was based on the decision tree consisted of eleven rows and eighteen columns (based on eleven water resources and eighteen affecting parameters on priority in both normal and drought). Using different types of parameters in the matrix with various units and comparing their effects is an advantage for TOPSIS model. The 10 parameters used for prioritization in the matrix were included of: cost, social acceptance, unexpected pollution, water quality, vulnerability to floods and earthquakes, the camouflage, temperature, potential evaporation, distance from the city center and height from the sea level. Results showed that the most weights in normal and drought conditions were due to EC (0.08) and the cost of water production (0.06), respectively. While, the least weights, in the same conditions, were related to the parameters of resources heights from the sea level with 0.02 and 0.03. Results also showed that Esteghlal dam and Shamil Takht wells could be the best resources of drinking water, respectively, in normal and drought conditions, with the weights of 0.28 and 0.35, respectively. This is while in droughts in recent years, much of the drinking water of Bandar Abbas has been provided from the Minab dam and other has been supplied from Minab plain wells and Shamil Takht wells. It is suggested that same study perform applying another model in prioritizing and then the results compare with the current study. It is better to use more parameters such as hardness, evaporation and faults in the areas. Also it is recommended to use among coordinated subgroups and scoring reparative models in MADM and ELECTRE method for prioritizing drinking water. In these suggested methods, instead of ranking options a new concept known as non-ratings could be used, so that in this way ineffective options could be removed.